Nitramisole, an imidazothiazole derivative, is an anthelmintic. Nitramisole was effective against migrating Strongylus vulgaris larvae in ponies. Treatment of infected ponies with Nitramisole resulted both a clinical and radical cure.

Ciprefadol is an opioid analgesic drug. It binds with a high affinity to mu (Ki 4.2 nM) and kappa (Ki 2.5 nM) opioid receptors. In vivo, ciprefadol displays mixed antagonist/agonist activity in the mouse writhing and the rat tail heat tests: in low doses, the compound inhibits the analgesic effect of morphine, while at higher doses it displays analgesic effect. Chronic administration of ciprefadol to rhesus monkeys produced a marked physical dependence more severe than that of morphine, and its effect was consistent with what would be expected of a potent, long-lasting morphine-like agonist.

Cevipabulin is a synthetic, water-soluble tubulin-binding agent with potential antineoplastic activity. Cevipabulin appears to bind at the vinca-binding site on tubulin but seems to act more similar to taxane-site binding agents in that it enhances tubulin polymerization and does not induce tubulin depolymerization. The disruption in microtubule dynamics may eventually inhibit cell division and reduce cellular growth.

Batabulin or T138067 (2-fluoro-1-methoxy-4-pentafluorophenylsulfonamidobenzene) covalently and selectively modifies the beta1, beta2, and beta4 isotypes of beta-tubulin at a conserved cysteine residue, thereby disrupting microtubule polymerization. Cells exposed to batabulin become altered in shape, indicating a collapse of the cytoskeleton, and show an increase in chromosomal ploidy. Batabulin is equally efficacious in inhibiting the growth of sensitive and multidrug-resistant human tumor xenografts in athymic nude mice. Batabulin has been in clinical trials for the treatment of cancers (breast cancer, colorectal cancer, glioma, hepatocellular carcinoma, non-small cell lung cancer). It does not have clinical activity in the treatment of colorectal cancer and glioma. Batabulin development was discontinued.

ISOMETAMIDIUM (as a chloride salt) is widely used in tropical countries as an antiprotozoal agent to control animal trypanosomiasis. It is used principally in cattle but also in sheep, goats, buffalos, donkeys, horses, camels and dogs.

Cyprenorphine is a mixed agonist-antagonist of opioid receptors. In clinical trials, administration of cyprenorphine induced psychotomimetic effects in pre-operative patients.

Troxacitabine is a synthetic nucleoside analogue. It is a poor substrate for nucleoside transporters and gains entry into cells by passive diffusion. Intracellular conversion to its active triphosphate form is via deoxycytidine kinase. Incorporation of this metabolite into DNA results in immediate chain termination and apoptosis induction. It is the first nucleoside analog with anticancer activity that has an unnatural stereochemical configuration. The dose-limiting adverse reactions were stomatitis and hand–foot syndrome.

Berubicin, an anthracycline derivative, is a DNA binding agent and potent topoisomerase II poison. Reata Pharmaceuticals were developing it as a treatment for brain cancer as it can breach the blood-brain barrier. It had also been in early clinical trials for the treatment of lung cancer and malignant gliomas. However, studies have been terminated. In October 2006, it was granted orphan drug designation from the FDA for the treatment of malignant gliomas. According to a CNS Pharmaceuticals media release in April 2018, berubicin will be studied for glioblastoma patients, these investigations will be funded in part by an equity crowdfunding campaign.

Vadimezan (5,6-dimethyl(xanthenone-4-acetic acid), ASA404, DMXAA) is a fused tricyclic analogue of flavone acetic acid with potential antineoplastic activity. In pre-clinical mouse tumour models it was demonstrated that administration of Vadimezan rapidly leads to disruption of the existing vasculature in the tumour and consequent haemorrhagic necrosis of the tumour. This was consistent with the finding that a single dose of Vadimezan induced a prolonged reduction in the growth of xenografted tumours in animal models. The ability to disrupt the vasculature in these pre-clinical models has been attributed to a rapid induction of cytokines, particularly TNFα (tumour necrosis factor α), serotonin and nitric oxide, resulting in hemorrhagic necrosis and a decrease in angiogenesis. Despite the fact that the molecular targets for the drug remained unknown, the promising pre-clinical results led to Vadimezan being selected for clinical development. Results of Phase I trials showed some restriction of tumour blood flow within 24 h of treatment, although this was not as dramatic as seen in pre-clinical models. Unlike the animal models, there was also very little evidence for the rapid death of blood vessels or for increases in TNFα levels in human tumors. No difference in antitumour activity, cytokine induction or toxicity was observed between two parallel Phase I trials, one dosed weekly and the other dosed every 3 weeks. Therefore the drug proceeded to Phase II clinical trials, dosed every 21 days in combination with chemotherapeutic agents. These trials indicated the drug had small benefits in the treatment of non-small-cell lung cancer and prostate cancer. However, a subsequent Phase III clinical trial was not able to reproduce this response and clinical development was halted.

Ombrabulin is an experimental drug candidate discovered by Ajinomoto and further developed by Sanofi-Aventis for cancer treatment. Ombrabulin is a synthetic water-soluble analog of combretastatin A4, derived from the South African willow bush (Combretum caffrum), with potential vascular-disrupting and antineoplastic activities. Ombrabulin binds to the colchicine binding site of endothelial cell tubulin, inhibiting tubulin polymerization and inducing mitotic arrest and apoptosis in endothelial cells. As apoptotic endothelial cells detach from their substrate, tumor blood vessels collapse; the acute disruption of tumor blood flow may result in tumor necrosis. Ombrabulin has been used in trials studying the treatment of Sarcoma, Neoplasms, Solid Tumor, Neoplasms, Malignant, and Advanced Solid Tumors, among others. In January 2013, Sanofi said it discontinued development of Ombrabulin after disappointing results from phase III clinical trials.